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W. ROSENHAIN AND S. L. ARC HBUTT.

CONSTRUCTION OF AEROPLANE WINGS OR OTHER LIKE STRUCTURES. APPLICATION FILED JUT.Y 22,1919.

1,8223%. Patented Nov. 18, 1919.

IV. Rosanna/12111 6.L.Archbutt INVENTORS BY ATTORNEY r @hllttQE,

CONSTRUCTION 01F AEROPLANE-WINGS 0E, QTHER LIK E STRUCTURES.

messes,

Application filed July 22', 1919. Serial No. 312,59

To all whom it may concern:

Be it known that we, WALTER RosnNHAIN,

D. So, F. R. 8., and SYDNEY LEONARD ARCH- BUTT, 1 11C, both subjects of the King of Great Britain and Ireland, and both residing at the National Physical Laboratory, Teddington, in the county of Middlesex, England, have invented certain new and useful Improvements in the Construction of Aeroplane-Wings or other like Structures, ofwhich the following is a specification.

This invention relates to the construction of aeroplane wings or'other structures involving the employment of sheet metal or other material which'cannot readily be tensioned by hand or by'the application of a dope such as is usually employed for finally 'tensioning the fabric hitherto adopted for such structures.

The invention is principally intended to facilitate the employment of sheet metal, but it will be clear that it may be applied with equal effect and like advantage with fabric or with any other suitable flexible material.

It has hitherto been proposed in connection with the fastening of fabric upon structuresto provide grooves upon the structure situated near the edges of the fabric, so that the'latter may be secured in the grooves by means of ropes, fillets or the like, and incidental to such securing of the fabric the latter is'also tensioned.

F or metal sheet, however, with which this invention is principally concerned, such methods would be entirely unsuitable owing to the stifl'ness and rigidity of the metal with the consequent high tensile forces necessary to render the metal sheet sufficiently smooth for practical purposes.

Thepresent invention comprises a method a of securing sheet metal or other material upon aeroplane wings or other, like structures which consist in first stretching the material as tightlyas possible by hand or otherwise upon or around the structure, next securing the material in such position by suitable means, and finally further tensioning the material by the'use of fillets adapted to force the material into the grooves or de ressions formed in the structure.

he accompanying drawings illustrate one mode of carrying out the invention.

Figure 1 is a sectional view showing one form of wing constructed in accordance With the invention.

Specification of Letters Patent.

Patented nears, rare;

Fig. 2 is a fragmentary View on a larger scale.

In carrying our invention into efiect in one convenient manner, as forexample, in its application to the construction of, an aeroplane wing, the latter may be formed somewhat in the usual manner with two main spars a havingflanges Z) c at the top and bottom respectively, and around the framing of the wing the thin metal sheet d is initially stretched as tightly as is reason ably possible by hand or otherwise.

The flanged portions of the spars are formed with depressions or grooves preferably running longitudinally of the spars and into the four grooves thus formed fillets e are forced by bolts f, screws or other convenient devices or attachments so that the sheet metal will also thus be forced into the depressions and the final tensioning of the material will accordingly thereby be performed. The fillets may be made of Wood or light alloy or other suitable mate rial and are preferably so shaped'that when forced home into position they will be sub stantially flush with and conform to the outer surface of the wing while the screws or other like attachments may be countersunk or otherwise suitably arranged so that there need be no appreciable projection of vire, nut or other device above the ring surlace.

By such amethod of construction the metal sheet can be readily. tensioned to a satisfactory extent while there is no undue complication in the construction of the wing frame, and in fact it may be, possible to simplify the construction by omitting some or all of the bracing wires at present employed owing to the materialstrengthening or stifiening of the wing as awhole by'the frictional grip between the covering sheet and the flanges offthe main spars. Moreover, by'making the metal sheet of suficient thickness it may be possible .to utilize the covering itself to carry an appreciable part of the load of the wing the whole win in such case acting as a box girder of she. low section;

The sheet metal: or other thin material may be of any desired width, but preferably .of a width equal to the distance between the centers of adjacent ribs or slightly wider. I

The sheet. metal may be used in lengths sufficient entirelyto surround the" wing frame in fore and aft directions, so thatoneextend 7 smaller sheets, as additional joints may be joint only would be required which could then be placed beneath one of the tightening fillets. lets are screwed home or are sufliciently tightened, a frictional grip will be estab-' placedunder each tightening fillet. If such Joints take the,form of direct attachment,

as by nailing or riveting, to the wing structure, the limitation of the efiects of injury to a singlevpanel of the wing will be still more completely secured.

If, "t is found necessary after the straining fillets have been tightened the edges of the metal sheets may be nailed to the ribs, adjacent "sheets being made either to. butt against one another or to overlap one another slightly,- but it is quite possiblethat the powerful1 longitudinal tension of the sheets and thefrictional grip on the ribs or spars which will result therefrom will be sufiicient to take the wind pressure without positive attachmentof the sheets to the ribs. When the fillets are employed forsecuring the sheet material in position, the means adopted for fastening the material prior to the final tensioning may be of a temporary character.

It is to be understood that the invention is not to be confined to any particular construction or arrangement of wing frame Even in this case, when the fil- ,members formin I having top ad or other structure, nor to any particular number or shape ofribs, spars or other the structure, nor to any particular materlal with which the structure is to be covered.

Having now described our invention, what we claim as new and desire to secure by Let ters Patent is j I 1. A method of securing and tensioning relatively stifi' but flexible sheet material upon aeroplane wing supporting structures having top and bottom grooves, which consists in first stretching the material around the structure and securing it in position, placing fillets against the outer surface of the material at the points alined with the grooves, and finally passing a single tensioning device through both the fillets, material and supporting structure and simultaneously drawing the fillets into the grooves, whereby, both sides of the wing material will be simultaneously and equally-tensioned.

2. An aeroplane wing including a spar extending longitudinally of the wing and bottom grooves communicating through anaperture which extends entirely through the spar, relatively'stifi but flexible sheet material forming the top and bottom of the wing, fillets engaging said material and forcing the same into said grooves, and a single tensioning device extending through the fillets,'material and spar aperture for simultaneously tensioning both 'sides of the material;

3. A structure asdefined in claim 2 in which the sheet material is metal.

In testimony whereof we have signed our names to this specification.

WALTER ROSENHAIN. SYDNEY L. AROHBUTT. 

